1. Field of the Invention
The present invention relates to a small-sized antenna which is integrated into mobile devices, and the like.
2. Description of the Related Art
As next-generation wireless data communication technology, Bluetooth which uses a band of 2.4 GHz that can be used without a license has been in the limelight, and is integrated into mobile devices such as mobile phones, notebook PCs, PDAs (Personal Digital Assistances), etc., and is expected to become increasingly common.
Circuit components such as antennas, wireless modules, etc., used in the Bluetooth are required to be reduced in size and weight, and it is important to be small in the area occupied by an antenna to be mounted on a circuit.
Although, as a small-sized antenna for this Bluetooth, an inverted-F monopole antenna, or the like has been developed, it is very small (for example, 20 mm×3 mm×3 mm), so that, to mount it on a circuit substrate, a metal conductor which serves as an antenna has to be mounted by integrating it with a resin-molded body (e.g. see Japanese patent application laid-open Nos. 2002-299934 and 7-288422).
However, since, as mentioned above, the small-sized antenna for Bluetooth is very small (about 20 mm×3 mm×3 mm), and is resin-molded together with the metal conductor, sealing of the metal conductor and mold, and the like is required, and there is therefore the problem that the mold tends to be costly.
In particular, as small-sized antennas of this kind tend to be often improved in their shape, changing the mold accordingly would be more costly.